M1_INBSI
ID M1_INBSI Reviewed; 248 AA.
AC P06816;
DT 01-JAN-1988, integrated into UniProtKB/Swiss-Prot.
DT 01-JAN-1988, sequence version 1.
DT 23-FEB-2022, entry version 95.
DE RecName: Full=Matrix protein 1 {ECO:0000255|HAMAP-Rule:MF_04068};
DE Short=M1 {ECO:0000255|HAMAP-Rule:MF_04068};
GN Name=M {ECO:0000255|HAMAP-Rule:MF_04068};
OS Influenza B virus (strain B/Singapore/222/1979).
OC Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC Insthoviricetes; Articulavirales; Orthomyxoviridae; Betainfluenzavirus.
OX NCBI_TaxID=107417;
OH NCBI_TaxID=9606; Homo sapiens (Human).
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX PubMed=3788064; DOI=10.1016/0042-6822(86)90237-0;
RA Hiebert S.W., Williams M.A., Lamb R.A.;
RT "Nucleotide sequence of RNA segment 7 of influenza B/Singapore/222/79:
RT maintenance of a second large open reading frame.";
RL Virology 155:747-751(1986).
CC -!- FUNCTION: Plays critical roles in virus replication, from virus entry
CC and uncoating to assembly and budding of the virus particle. M1 binding
CC to ribonucleocapsids (RNPs) in nucleus seems to inhibit viral
CC transcription. Interaction of viral NEP with M1-RNP is thought to
CC promote nuclear export of the complex, which is targeted to the virion
CC assembly site at the apical plasma membrane in polarized epithelial
CC cells. Interactions with NA and HA may bring M1, a non-raft-associated
CC protein, into lipid rafts. Forms a continuous shell on the inner side
CC of the lipid bilayer in virion, where it binds the RNP. During virus
CC entry into cell, the M2 ion channel acidifies the internal virion core,
CC inducing M1 dissociation from the RNP. M1-free RNPs are transported to
CC the nucleus, where viral transcription and replication can take place.
CC {ECO:0000255|HAMAP-Rule:MF_04068}.
CC -!- FUNCTION: Determines the virion's shape: spherical or filamentous.
CC Clinical isolates of influenza are characterized by the presence of
CC significant proportion of filamentous virions, whereas after multiple
CC passage on eggs or cell culture, virions have only spherical
CC morphology. Filamentous virions are thought to be important to infect
CC neighboring cells, and spherical virions more suited to spread through
CC aerosol between hosts organisms. {ECO:0000255|HAMAP-Rule:MF_04068}.
CC -!- SUBUNIT: Homodimer and homomultimer. Interacts with NEP. Binds
CC ribonucleocapsid by both interacting with genomic RNA and NP protein.
CC May interact with HA and NA. Cannot bind NP without genomic RNA.
CC {ECO:0000255|HAMAP-Rule:MF_04068}.
CC -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000255|HAMAP-
CC Rule:MF_04068}; Peripheral membrane protein {ECO:0000255|HAMAP-
CC Rule:MF_04068}; Cytoplasmic side {ECO:0000255|HAMAP-Rule:MF_04068}.
CC Host nucleus {ECO:0000255|HAMAP-Rule:MF_04068}.
CC -!- MISCELLANEOUS: Influenza B virus genome RNA segment 7 encodes the M1
CC and BM2 (AC P08383) proteins. Normal translation produces the M1
CC protein. The M1 termination codon overlaps the BM2 initiation codon in
CC an overlapping stop-start pentanucleotide 5'-UAAUG-3'. Termination of
CC M1 translation triggers reinitiation on the BM2 AUG in the +2 open
CC reading frame.
CC -!- MISCELLANEOUS: Most abundant protein in virion. When expressed alone
CC can form virus-like particles in transfected cells. {ECO:0000255|HAMAP-
CC Rule:MF_04068}.
CC -!- SIMILARITY: Belongs to the influenza viruses Matrix protein M1 family.
CC {ECO:0000255|HAMAP-Rule:MF_04068}.
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DR EMBL; M14909; AAA67100.1; -; Genomic_RNA.
DR PIR; A25619; MFIVB1.
DR SMR; P06816; -.
DR PRIDE; P06816; -.
DR Proteomes; UP000137758; Genome.
DR GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0003723; F:RNA binding; IEA:UniProtKB-UniRule.
DR GO; GO:0039660; F:structural constituent of virion; IEA:UniProtKB-UniRule.
DR GO; GO:0046761; P:viral budding from plasma membrane; IEA:UniProtKB-UniRule.
DR Gene3D; 1.10.10.180; -; 1.
DR Gene3D; 1.20.91.10; -; 1.
DR HAMAP; MF_04068; INFV_M1; 1.
DR InterPro; IPR036039; Flu_matrix_M1.
DR InterPro; IPR013188; Flu_matrix_M1_C.
DR InterPro; IPR001561; Flu_matrix_M1_N.
DR InterPro; IPR015423; Flu_matrix_M1_N_sub1.
DR InterPro; IPR015799; Flu_matrix_M1_N_sub2.
DR InterPro; IPR037533; INFV_M1.
DR Pfam; PF00598; Flu_M1; 1.
DR Pfam; PF08289; Flu_M1_C; 1.
DR SMART; SM00759; Flu_M1_C; 1.
DR SUPFAM; SSF48145; SSF48145; 1.
PE 3: Inferred from homology;
KW Host nucleus; Membrane; Reference proteome; RNA-binding;
KW Viral matrix protein; Virion.
FT CHAIN 1..248
FT /note="Matrix protein 1"
FT /id="PRO_0000078874"
FT REGION 1..164
FT /note="Membrane-binding"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
FT REGION 165..248
FT /note="RNP-binding"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
FT MOTIF 101..105
FT /note="Nuclear localization signal"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
SQ SEQUENCE 248 AA; 27474 MW; 514EACFC5C21CAAD CRC64;
MSLFGDTIAY LLSLTEDGEG KAELAEKLHC WFGGKEFDLD SALEWIKNKR CLTDIQKALI
GASICFLKPK DQERKRRFIT EPLSGMGTTA TKKKGLILAE RKMRRCVSFH EAFEIAEGHE
SSALLYCLMV MYLNRGNYSM QVKLGTLCAL CEKQASHSHR AHSRAARSSV PGVRREMQMV
SAMNTAKTMN GMGKGEDVQK LAEELQSNIG VLRSLGASQK NGEGIAKDVM EVLKQSSMGN
SALVKKYL
